But I've noticed a lot of other benefits, too.

Old age has a way of reminding you that time is short. People your age--or younger--that you care about start passing away, sometimes with scant notice. One's energy level and memory are not what they used to be. Weight is easier to put on, harder to lose. Ailments start creeping in--or sometimes rushing in.
Life becomes more of a gift, less of a burden. One hopes for many more years, especially productive and healthy ones. But clearly most of life is in the rear-view mirror, and the road ahead may be much shorter and more difficult than we hope for. And that is a good thing to ponder.